1. Field of the Invention
This invention relates to exhaust systems. More particularly, it relates to damage protection apparatus for an exhaust pipe for tractors, trucks and the like.
2. Description of the Prior Art
For many years there has been a need for protection of an exhaust pipe which will not bend on a tractor, trailer truck or the like, whether below or above the hood when it touches or strikes a limb in a field or top frame of a garage, terminal or the like. U.S. Pat. No. 3,173,710 provides an interconnection between an engine exhaust manifold and a muffler which readily disconnects whenever the cab is tilted. There is a double-bell unit between the muffler and an expansible hose unit, the bell unit having a spring therein which tubes in the bell unit apart. U.S. Pat. No. 4,378,945 teaches a bellows-type spring seal with coil springs encircling the bellows. U.S. Pat. No. 4,339,919 discloses a relatively thin, flexible, generally vertical metal hanger made up of a plurality of thin, stainless steel, strips overlaid on one another to flexibly connect and support a muffler to an engine or frame. The muffler is connected to an internal combustion engine by a rigid exhaust pipe. In U.S. Pat. No. 4,567,817 the inventors present a vehicle exhaust pipe which extends vertically through the vehicle interior, up to a point above the roof, and is surrounded by a protective tube. A collective funnel on the vehicle rood overlaps the end of the exhaust pipe, has a transfer pipe, is pivotally mounted on suspension elements and is resiliently directed into an upward-pointed position. A muffler disclosed in U.S. Pat. No. 4,308,930 mounted on the hood of an engine compartment has an outer cylindrical member, with openings therein, an inner cylindrical member connected to an exhaust pipe and an exhaust pipe connected to the upper end of the outer cylindrical member, the outer cylindrical member being mounted on the hood so that its lower half is positioned below the hood. From the disclosure of U.S. Pat. No. 3,352,573 it is found that a pipe for diesel exhaust may be provided with a hinged connector so that a stack elevated high above the truck and cab body may be supported without whipping due to high wind, motor vibration and lowered for moving under low bridges and through doors of buildings. U.S. Pat. No. 2,489,481 teaches an exhaust pipe extension that is damage proof itself and protects the exhaust pipe from damage by striking obstructions. A compression spring surrounds a guide bar. A spring is provided to yieldingly resist forward movement of an outer tube 20. In U.S. Pat. No. 2,489,480 is described how backing into an obstruction will compress a close-coiled section of a spring of an exhaust pipe extension and slide it forward.
None of the foregoing patents teaches how to keep from breaking off an exhaust pipe when one drives a vehicle such as a tractor or a cab for a tractor-trailer or the like under one or more low branches when plowing a field or the like or driving such vehicle under a low garage door frame or the like.